This invention relates generally to the abatement of contaminant laden industrial process emissions and more specifically, to a ducting and valving system that directs and controls the flow of such emissions to and through a two chamber regenerative thermal oxidizer.
Industrial process emissions often contain combustible contaminants and/or odors that, if released to atmosphere, have the potential of polluting the environment. Thermal oxidizers increase the temperature of such process emissions to a temperature above the ignition temperature of the contaminants therein so as to oxidize the contaminants. Characteristically, flow control valves are used to direct the emissions to one or more regenerators for preheating prior to thermal oxidation.
One problem that materially effects the efficiency of such oxidizers is short circuiting of the thermal oxidizer by contaminated emissions incident to opening and closing of the valves required for control of fluid flow to and from the regenerators. Obviously, short circuiting of emissions between flow control valves in the partially open condition seriously compromises the efficiency of the oxidizer. Problems inherent in the design of two chamber regenerative oxidizers complicates the problem.
More specifically, as the chambers of known two chamber regenerative oxidizers switch from inflow to outflow, there is both a momentary change in system pressure due to simultaneous opening and closing of all valves and a momentary period where incoming contaminant laden emissions short circuit the common oxidation chamber. Pressure variations place excessive loads on the fluid moving equipment and are unacceptable in the processes being controlled via the regenerative oxidizers. Short circuiting of the oxidation chamber compromises the efficiency of the system.